crystal Structure and Electrospray Ionization Mass Spectrometry, Electron Paramagnetic Resonance, and Magnetic Susceptibility Study of [Cu2(ascidH2)(1,2-.mu.-CO3)(H2O)2].cntdot.2H2O, the Bis(copper(II)) Complex of Ascidiacyclamide (ascidH4), a Cyclic Peptide Isolated from the Ascidian Lissoclinum patella

Brenk, Anna L. van den; Byriel, Karl A.; Fairlie, David P.; Gahan, Lawrence R.; Hanson, Graeme R.; Hawkins, Clifford J.; Jones, Ashley; Kennard, C. H. L.; Moubaraki, Boujemaa; Murray, Keith S.

doi:10.1021/ic00094a019

Cited by 116 publications

(67 citation statements)

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“…1 are in good agreement with crystal structures of similar patellamide systems [36]. For example, the average Cu-N distance of the two copper atoms found here is 2.038 (Cu1) and 2.075 (Cu2) Å, whereas in the crystal structures values of 2.002 and 2.025 Å were obtained [36].…”

Section: Carbonate Binding To a Dicopper Patellamide Complexsupporting

confidence: 90%

“…Since these orbitals are orthogonal and located on different metal centers the interaction of the two unpaired electrons can be ferromagnetically coupled into a triplet spin state or antiferromagnetically coupled into a singlet spin state. As a consequence, these spin states are degenerate (DE ST = 0.0 kcal mol À1 ) in agreement with experimental EPR studies that observed weak ferromagnetic interaction [36]. In mononuclear heme and nonheme oxoiron complexes the degeneracy of spin states of the oxidant can lead to two-state-reactivity patterns with different reaction barriers on each spin state surface [49][50][51].…”

Section: Carbonate Binding To a Dicopper Patellamide Complexsupporting

confidence: 85%

“…It has been anticipated that carbonate binding is essential for the putative catalytic activity of the dicopper patellamides or alter- natively acts as an inhibitor [36]. 4 .…”

Section: Carbonate Binding To a Dicopper Patellamide Complexmentioning

confidence: 99%

“…The basic structure of patellamides consists of a cyclic octapeptide containing two thiazole and two oxazoline rings (Scheme 1). The structure binds two metal atoms, typically copper atoms although studies of other bound metals have been reported as well [36][37][38][39][40]. The patellamides are split into two classes, symmetric and asymmetric, distinguished from each other by the absence or presence of a phenylalanine residue, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…Each patellamide has five characteristic side chains (L 1 -L 5 ) that vary among the different patellamides. In addition, it has been shown that patellamide dicopper complexes have an unusual large affinity to carbonate, which has been implicated as being essential for the catalytic properties of the system although it is not clear how and why this is the case [36]. Thus, to find out how carbonate, hydrogen peroxide, water and molecular oxygen coordinate to a dicopper patellamide and how this may influence the intrinsic and putative catalytic properties of the complex we present here results of a density functional theory study on a series of dicopper patellamide models (Scheme 1) with a variety of ligands bound to copper.…”

Section: Introductionmentioning

confidence: 99%

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Density functional theory studies of oxygen and carbonate binding to a dicopper patellamide complex

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Bagherzadeh

Milne

et al. 2008

Journal of Inorganic Biochemistry

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a b s t r a c tIn this work we present results of density functional theory (DFT) calculations on dicopper patellamides and their affinity for molecular oxygen and carbonate. Patellamides are cyclic octapeptides that are produced by a cyanobacterium, and may show promise as therapeutics. Thus, carbonate binding to a dicopper patellamide center gives a stable cyclic octapeptide with a twist of almost 90°. The system exists in closelying open-shell singlet and triplet spin states with two unpaired electrons in orthogonal r Ã orbitals on each metal center. Subsequently, we replaced carbonate with dioxygen and found a stable Cu 2 (l-O) 2 diamond shaped patellamide core. In this structure the original dioxygen bond is significantly weakened to essentially a single bond, which should enable the system to transfer these oxygen atoms to substrates. We predicted the IR and Raman spectra of the Cu 2 (l-O) 2 diamond shaped patellamide structure using density functional theory and found a considerable isotope effect on the O-O stretch vibration for 16 O 2 versus 18 O 2 bound structures. Our studies reveal that carbonate forms an extremely stable complex with dicopper patellamide, but that additional molecular oxygen to this system does not give a potential oxidant. Therefore, it is more likely that carbonate prepares the system for dioxygen binding by folding it into the correct configuration followed in the proposed catalytic cycle by a protonation event preceding dioxygen binding to enable the system to reorganize to form a stable Cu 2 (l-O) 2 -patellamide cluster. Alternatively, carbonate may act as an inhibitor that blocks the catalytic activity of the system. It is anticipated that the Cu 2 (l-O) 2 -patellamide structure is a potential active oxidant of the dicopper patellamide complex.Crown

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Section: Carbonate Binding To a Dicopper Patellamide Complexsupporting

confidence: 90%

Section: Carbonate Binding To a Dicopper Patellamide Complexsupporting

confidence: 85%

“…It has been anticipated that carbonate binding is essential for the putative catalytic activity of the dicopper patellamides or alter- natively acts as an inhibitor [36]. 4 .…”

Section: Carbonate Binding To a Dicopper Patellamide Complexmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Density functional theory studies of oxygen and carbonate binding to a dicopper patellamide complex

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Bagherzadeh

Milne

et al. 2008

Journal of Inorganic Biochemistry

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Gas-phase fragmentation of coordination compounds: loss of CO2 from inorganic carbonato complexes to give metal oxide ions

Dalgaard¹,

McKenzie²

1999

J. Mass Spectrom.

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Effects of amino acids and chirality for molecular folding of desoxazoline-ascidiacyclamide derivatives: X-ray crystal structures of four cyclic octapeptides including unusual amino acids,cyclo(-Ile-aThr-D-Val-Thz-)2,cyclo(-Ala-aThr-D-Val-Thz-Ile-aThr-D-Val-Thz-),cyclo(-Val-aThr-D-Val-Thz-Ile-aThr-D-Val-Thz-), andcyclo(-Ile-aThr-Val-Thz-Ile-aThr-D-Val-Thz-)

et al. 2001

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Desoxazoline derivative of ascidiacyclamide (1), cyclo(–L‐Ile–L‐allo‐threonine–D‐Val–thiazole–)2, was modified to disturb the C2‐symmetry. An Ile1 residue of 1 was replaced for Ala (2) or Val (3), and the D‐Val3 residue was replaced for Val (4). The crystal structures of 1–4 were analyzed by x‐ray diffraction methods. The molecules of all compounds were folded and this type of structure was not observed in x‐ray structures of ascidiacyclamide derivatives so far except for patellamide D. The folding patterns of 1–4 were similar to each other and resembled that of patellamide. The asymmetric modifications at position 1 caused the conformational changes at local area, and these were related with the peptide–peptide and peptide–solvent interactions. Despite the diverse backbone conformation by the epimeric modification at position 3, the entire molecule of 4 was folded. These results mean that (1) the desoxazoline‐ascidiacyclamides favored the folded structures and (2) the modifications of the side chain size at position 1 and the chirality at position 3 brought the local conformational changes to derivatives, suggesting that (3) the lack of the oxazoline block leads to conformational flexibility of 1–4, which accepts the conformational change with no drastic change on the entire structure. © 2001 John Wiley & Sons, Inc. Biopolymers 58: 295–304, 2001

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Cited by 116 publications

References 5 publications

Density functional theory studies of oxygen and carbonate binding to a dicopper patellamide complex

Density functional theory studies of oxygen and carbonate binding to a dicopper patellamide complex

Gas-phase fragmentation of coordination compounds: loss of CO2 from inorganic carbonato complexes to give metal oxide ions

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